Yarra valley winemakers are feeling the heat as bushfires rip through Victoria's vineyards.

Scorching temperatures and wind have spread the fires, razing vineyards in the state.

Roundstone winery, its restaurant and the owner's home at Yarra Glenn has been burnt down along with 8 hectares of grapes. Other Yarra wineries including Domaine Chandon, Lance Family Vineyards and Punt Road experienced some damage.

Foster's has also lost 40 hectares of Pinot Noir, Shiraz and Merlot in the Yarra. Troy Hey, Foster's spokesman, said: "We are still assessing the damage in and around the Yarra Valley and throughout Victoria as we have not been able to get into all regions because of the continued fire threat.. We expect that the full impact won't be known for some time as we have to consider the damage to our own and our contracted growers' vineyards."

Growers could lose much of their harvest due to smoke tainting grapes.